12. e1c1  12... e8c8 Here and on the next move it might have been a good idea for Wei to insert the moves h6-h5 and h2-h3, thus softening the white kingside. 13. e3e4  13... d5e4 All of this is very logical, but now White has an extra and unpleasant choice. 14. f3a3 With the dark-squared bishop stuck on f8, this queen swing looks extremely unpleasant for Black. He has very concrete problems to solve.